Method and arrangement for testing the liquid in washing machines

ABSTRACT

In a washing machine, a galvanic element in the form of a pair of electrodes of different metals is mounted within the container for the washing liquid which acts as an electrolyte. The electrodes continuously sense the degree of dissociation of the washing liquid during the washing process with additional detergent or washing agent being added in response to the degree of dissociation. The washing liquid will contain the dirt released from the laundry being washed, the fresh water initially added at the beginning of the washing process and the washing agent or detergent.

0 United States Patent 1 51 3,645,669

Rausch 1 Feb, 29, 1972 [54] METHOD AND ARRANGEMENT FOR 2,940,287 6/1960 Henderson .324/30 TESTING THE LIQUID IN WASHING 3,101,239 8/1963 Warren MACHINES 3,101,240 8/1963 Mathews... 2,218,698 10/1940 Clark [72] Inventor: Gerhard Rausch, Obere Waldstr, 14, 2,430,668 1 1/1947 Chamber|in M r g Bordensee, Germany 3,114,253 12/1963 Morey et al ..68/12 R [22] filed: Feb. 1969 Primary Examiner-Mayer Weinblatt PP 813,381 Attorney-Edmund M. .laskiewicz Related US. Application Data 57 1 ABSTRACT [63] gg f z g of In a washing machine, a galvanic element in the form of a pair 19 a an one of electrodes of different metals is mounted within the container for the washing liquid which acts as an electrolyte. The .[52] Cl 1 6 electrodes continuously sense the degree of dissociation of the [51] Int Cl B68) 3/00 washing liquid during the washing process with additional de- I tergem or washing agent being added in response to the [58] Field ofSearch ..8/137, 142, 324/30, 68/12 degree dissociation The washing liquid will Contain the din released from the laundry being washed, the fresh water ini- [56] References cued tially added at the beginning of the washing process and the UNITED STATES PATENTS washing agent or detergent- Martz, Jr. ..8/137 4 Claims, 5 Drawing Figures PAIENTEDFEB29 m2 sum 1 or 2 IN VEN TOR GERHARD RAUSCH A Horneys FIGS IN VEN TOR y GERHARD RAUSCH MW A Horneyfi PAIENTEDFEB29 m2 sum 2 0F 2 FIGS.

METHOD AND ARRANGEMENT FOR TESTING TI-IE LIQUID IN WASHING MACHINES CROSS REFERENCES TO RELATED APPLICATION The present application is a continuation-in-part of the copending application Ser. No. 322,220, filed Nov. 7, 1963 now abandoned, by the same named inventor.

The present invention relates to the washing of fabrics in liquid in a washing machine, more particularly, to a method and arrangement for testing the active force of the liquid in fully automatic washing machines during the washing process.

A table is generally supplied with each washing machine, showing which washing agent and what quantities thereof must be supplied in the machine during a washing process, depending on the type of laundry being washed and how dirty it In fully automatic washing machines the washing agent, which has been previously supplied in accordance with the table, is added at precisely defined intervals of time by means of the program control switch, but without taking into account the actual active force of the liquid. For very soiled laundry the operating tables recommend using large amounts of washing agents, so that there is a danger of the washing liquid being already oversaturated at the beginning of the washing process and consequently forming too much foam, with the result that the activity of the liquid is appreciable reduced.

It is the object of this invention to avoid this disadvantage of known washing machines and to provide an improved method and arrangement for constantly testing the activity of the washing liquid during a washing process and for accurately adding the washing agent with respect to both quantity and timmg.

This object is achieved, according to the present invention by using the degree of dissocation of the washing and/or rinsing liquid as a control value.

Recent methods of developing washing machines have shown that in modern machines the washing process, with a view to obtaining the desired degree of cleanliness in the laundry, is not only based on thermal, chemical and mechanical action, in that the laundry is agitated in the drum, acted on by the liquid and heated to boiling point, but also that a very important and effective electrical process takes place during the washing operation. In the majority of cases the fibers not only of synthetic materials but also of linen and cotton have a static electrical charge of negative potential, whereas the dirt particles clinging to the fibers have a positive static charge. In correct appreciation of this fact, modern detergents recommended for washing machines are adapted to the electrical process taking place during the washing operation, and reverse the potential of the dirt particles, so that these also receive a static electrical charge of negative potential and are thus repelled from the fiber. The. repelled dirt particles are encased in the liquid by liquid-ions of opposite polarity, so that they cannot cling to the fibers again.

In cases where there are a large number of dirt particles, i.e., when very soiled laundry is being washed, the gathering of ions of the same polarity on each dirt particle disturbs the ion balance of the washing liquid, with the result that its degree of dissociation or ionization is constantly varying during the washing process. Also in the case of very soiled laundry, more dirt particles may be released from the laundry than ions of opposite polarity are added through the detergent. As a result, some of the released dirt particles will not be encased in the washing liquid by the liquid ions of opposite polarity and these free dirt particles will then fall back upon the fabrics being laundered. This action will produce the well-known gray color of laundry.

Since, following from these considerations, the degree of dissociation has a causative relationship to the number of dirt particles encased in the liquid and enables inferences to be made about the cleansing power still inherent in the liquid, the degree of dissociation is, according to the invention, constantly monitored during the washing process and appropriate controls are effected depending on this degree.

In order to ascertain the degree of dissociation of the washing liquid, the invention employs a galvanic element whose electrodes are made of two different metals, an electrolyte being formed by the washing and/or rinsing liquid and the terminal voltage thereof being used as a value indicating the degree of dissociation of the liquid.

The degree of dissociation of the washing and/or rinsing liquid forming the electrolyte for the galvanic element determines the internal resistance and thus the terminal voltage of the element, so that the latter may be used as a control value for the appropriate regulation.

According to the invention, if control values of a higher capacity are to be obtained it is advantageous to using two electrodes immersed in the washing and/or rinsing liquid and located in an electrical circuit, of which the electrical resistance is used as a value responsive to the degree of dissocation of the liquid.

As the degree of dissocation of the liquid also depends to a substantial extent on the degree of dissociation of the fresh water comprising the liquid, misleading control values might be obtained therefore compensation of the two degrees of dissocation is necessary. According to the invention this compensation is provided, in that the degree of dissociation of the fresh water supplied is also measured, and the difference in the degrees of dissociation of the washing and/or rinsing liquid and of the fresh water is used as the control value.

As a result of this feature, the control value is determined not by the absolute but merely by the relative amount of the degree of dissociation of the washing and rinsing liquid.

In fully automatic washing machines it is possible, according to the invention, for the control value to be used for regulating the amount of washing agent added.

By this process the addition of washing agent is regulated automatically as soon as the value of the degree of dissociation indicates that the activity of the washing liquid has decreased.

According to the invention, in nonautomatic or semiautomatic washing machines the control value may be used for controlling audible or visual signals.

The operation of visual or audible signals by the control value enables the operator of the machine to know whether and when washing agents should be added.

For certain washing processes and certain, particularly high-speed washing machines, it may be advantageous for the supply of washing agent to be regulated by the control value not only when a given degree of dissociation is reached but, according to an important feature of the method, for the reduction in time of the degree of dissociation of the differential quotient of the washing machine also to be used as a control value.

As a result of this feature regulation, for example of the supply of washing agent to a washing machine, takes place as soon as the differential quotient, related to the reduction in the degree of dissociation in the unit of time, reaches a given predetermined value. This is measured with known, very accurate differential quotient meters, enabling sufficient quantities of washing agents to be added, for example continuously, to the washing machine to keep the activity of the liquid constantly at the correct level.

The arrangement for carrying out the method according to the invention is distinguished by two electrodes located in the region of the washing and/or rinsing liquid and possibly of the fresh water.

Further explanation of the features of the invention is given by the accompanying drawings which, in conjunction with the detailed description thereof, reveal further features and advantages of the invention.

In the drawings:

FIG. 1 is a graph showing the relationshipbetween the control values measured and the temperature of the washing liquid and the degree of cleansing obtained when laundry soiled to a normal degree is washed;

FIG. 2 is a graph similar to that in FIG. 1 but the curves being for the washing of very soiled laundry;

FIG. 3 diagrammatically shows the arrangement of the electrodes in the region of the washing and/or n'nsing liquid in a drum washing machine;

FIG. 4 is a diagram representing a switching arrangement for estimating the control size for operating a magnetic valve; and

FIG. 5 is a diagram representing the arrangement of electrodes in the region of the fresh water supply.

When the measurements were taken to obtain the curves in FIG. 1, a galvanic element comprising a copper and a zinc electrode was mounted in the region of the washing and/or rinsing liquid in a drum washing machine and the current was measured and recorded by a curve tracer. In the graph in FIGS. 1 and 2 time t is shown by the horizontal axis, current i by the vertical axis, the temperature of the liquid in degrees Centigrade and the extent .to which the laundry is cleaned in percentages. It will be seen that the temperature curve 1 rises almost linearly from the room temperature of about 20 and then, on reaching boiling temperature between 90 and l00, becomes almost uniform.

The current curve 2 shows that the current measured at the electrodes at first rises almost proportional to the heating of the liquid, the dirt particles being freed from the laundry at about 70 C. The degree of dissociation of the liquid hardly varies, since quite small quantities of ions are sufficient to encase the smaller dirt particles, so that the ion balance is not disturbed and the degree of dissociation not altered. But as soon as the liquid is heated to approximately 90 C. the fat particles, which require considerably larger amounts of ions to encase them, also start to be released from the laundry, with the result that the ion balance is appreciably disturbed and the degree of dissociation measurably altered, as can be seen from the far more level course of the current curve 2.

It will be seen from FIG. i that the cleansing curve 3 extends substantially proportionally with the current curve 2 until a liquid temperature of approximately 90 is reached, after which it rises only slightly in accordance with the changed degree of dissociation of the liquid, and only after a given length of time shows the laundry to be almost '100 percent clean. When this point is reached, no more dirt particles are being released from the laundry, so that there are no further changes in the degree of dissociation of the liquid, as apparent from the almost uniform course of the current curve The degree of dissociation or ionization of the washing liquid is largely independent of the types and kinds of dirt and soil found in the laundry, kinds of fabric, and the hardness of water. Since the laundry process is essentially electrical in nature the types and kinds of dirt and soil found in the fabrics have only a negligible effect on the operativeness of the present invention. Furthermore, since the degree of dissociation of the washing liquid is an indication of the ionization or number of ions existing in the washing liquid it is apparent that the ions of opposite polarity which must be added in the washing agent must be such to properly neutralize the ions in the washing liquid. Here again it must be pointed out that the present invention utilizes different degrees of dissociation in the washing liquid and not the absolute degree of dissociation as ascertained at any one time. By comparing the differing degrees of dissociation encountered during the washing process with a reference degree of dissociation the correct amount of washing agent will be always added to the washing liquid.

FIG. 2 shows the curves obtained when very heavily soiled laundry is washed. It will be seen that, compared with FIG. 1, the current curve 2 rises considerably less sharply and then drops again, since the fat particles released form a very large number of ions and alter the degree of dissociation of the liquid to a greater extent. It will be seen from the cleansing curve 3 that, at this moment, for example, a 50 percent degree of a cleansing is reached, and this does not increase although the washing process is continued. At the point of time I, for example, fresh washing agent therefore must be added to the liquid in order to reestablish its ion balance, and increase its activity, this change being shown by a further rise in the current curve 2. As more fat particles are released from the laundry during this process, the cleansing curve 3 shows a further rise until the ion balance in the liquid is reestablished and the degree of dissociation of the liquid is changed sufficiently to make the current curve 2 drop again. The degree of cleansing obtained, approximately can consequently not be further increased unless more washing agent is added at the point of time II and the ion balance of the liquid thus reestablished. This is shown by the renewed rise of the curve 2, and enables the laundry to reach the desired degree of cleanliness of approximately I00 percent.

The present invention utilizes the relative degree of dissociation between a completely active washing liquid, i.e., fresh water and detergent, and a washing liquid which has been partially consumed by the addition of dirt particles released from the laundry being washed. Thus, the physical characteristics of the electrodesemployed are unimportant since it is only necessary to determine the different degrees of dissociation. The degree of dissociation of the fully active washing liquid may be calibrated to the actual values sensed by the electrodes. The invention depends on differences between the degree of dissociation sensed at the beginning of the washing cycle and the degrees of dissociation encountered as the washing process continues. These sensed differences will control the addition of the washing agent. The actual values of current and voltage indicated by the electrodes is unimportant as long as these values bear a relationship to the degree of dissociation of the washing liquid.

FIG. 3 diagrammatically shows a drum washing machine with a housing 4 and a washing drum 5 rotatably mounted-in a liquid container 6. For the purpose of adding washing agents, the container 6 is equipped with a funnel-shaped filling connection 7 with its orifice below a flap 8 in the housing 4. Electrodes 9, 10 are provided in the region of the washing and/or rinsing liquid and are mounted with insulation in the wall of the container 6, their terminals 1 1, 12 extending to the outside of the container 6 and being connected to corresponding control leads 13, 14. The leads l3, 14 may be connected to an outside source of electric power and lead to a relay 15, which may regulate a control lamp 16 and/or buzzer 17 according to the voltage at the terminals 11, 12. It is possible for the switching process of the relay 15 to be impeded by a thermostat 18 so long as the increase in the current in the leads l3, 14 is substantially proportional to the increase in the temperature of the liquid. But when heavily soiled laundry is being washed, as soon as the degree of dissociation of the liquid undergoes a great change and the current curve 2 in FIG. 2 no longer rises substantially proportionally to the temperature curve 1 but instead drops, the blocking means of the relay 15 are released and the relay closes the circuit for the control lamp 16 or buzzer 17. The staff operating the washing machine are thus notified that the activity of the liquid has dropped below the necessary level and that an additional dose of washing agent is required.

The term automatic washing machine" as applied to many of the present day washing machines is actually misleading. Such washing machines merely have a program control circuit which controls the duration of time of each step in a wash cycle. Other than this time control function there is no automatic control of any phase of the washing cycle with respect to, for example, the condition of the washing liquid, the quantity of detergent which should be added, the fabric and the amount of dirt in the fabric and released in the washing liquid. However, a washing machine according to the present invention can be said to be fully automatic since such a machine regulates the washing process with reference to the actual conditions of the washing liquid as sensed during the washing process.

FIG. 4 is a diagram showing a possible application of the present invention to a washing machine automatic in the sense of thisinvention, wherein a magnetic valve l9,located in a pipe 20 supplying fresh water to a washing agent container 21, is controlled by the relay 15. The container 21 is mounted below the flap 8 and equipped in known manner with an intermediate perforated bottom 22 and an outlet pipe 23 discharging into the filling connection 7. A sufficient amount of washing agent is placed in the container 21 at the beginning of the washing process and is left on the intermediate perforated bottom 22. Only when fresh water is supplied through the pipe 20 is the washing agent flushed through the bottom 22 and into the filling connection of the washing machine. The magnetic valve 19 is controlled in the usual way at a suitable time by the program switch (not shown) of the washing machine by means of switching leads 25, 26. It will be appreciated that, if the relay 15 is connected in parallel with the magnetic valve 19, more washing agent can be added automatically as soon as the degree of dissociation of the washing liquid has changed sufficiently to make the relay l5 respond.

FIG. 5 is a further diagram illustrating the application of another feature of the process to a fully automatic washing machine where the degree of dissociation of the fresh water supplied is measured in addition to and simultaneously with that of the washing liquid. For this purpose an electrode container 27 provided with electrodes 28, 29 is mounted in the fresh water pipe 20. The electrodes 28, 29 are connected by relay leads 30, 31 to a differential relay 32, of which the reference voltage is supplied by the electrodes 9, through control leads 13, 14. This arrangement makes it possible to compare the variation in the degree of dissociation of the washing liquid with the degree of dissociation of the fresh water supplied, and to adjust the supply of washing agent accordingly. As shown in broken lines in FIG. 5, it is also possible for an auxiliary relay 33 operating a further magnetic valve (not shown) to be controlled by the electrodes 28, 29 through leads 35. This arrangement, for example, enables accurately dosed amounts of a softener to be added fully automatically to the washing liquid depending on the hardness of the fresh water supplied. This is particularly advantageous when the washing machines are not stationary and must be connected to fresh water sources in various places.

According to another feature of the process, the relay may be controlled by a suitable differential quotient meter 34 of a type known in the art and connected to the electrodes 9, 10 by leads 13, 14 as shown in broken lines in FIGS. 3 and 4. [n such a case it is unnecessary to supply the relay 15 with a reference value, such as the temperature of the washing liquid through a thermostat 18, since the reduction in the degree of dissociation of the washing liquid per unit of time is used as the control value. This arrangement makes it possible for the supply of washing agent to be automatically regulated almost immediately after each change in the degree of dissociation, so that the washing process is considerably shortened.

The present invention may be more readily understood by referring to the subsequent specific examples.

EXAMPLE I Two electrodes of copper and aluminum respectively were mounted in the cylindrical drum of a washing machine. Each electrode had an area of 50 cm. and electrodes were posi tioned 5 cm. apart. The electrodes were capable of producing a terminal voltage of about 2 volts. An ammeter having a range of 150 ma. was connected in the external electrical circuit interconnecting the electrodes.

The cylindrical drum had a capacity of approximately 120 liters. Into this drum 30 liters of fresh water were admitted. The water was at a temperature of 90 C. 200 grams of a detergent were introduced. The detergent was DIXAN manufactured by Henkel of Diisseldorf, Germany. Approximately 5 kilos of soiled laundry consisting of various articles of clothing were placed in the drum.

rear.

At the beginning of the washing process before any dirt particles were released from the laundry the ammeter indicated a current of lOO ma. After the washin process had proceeded so that some dirt was removed from t e laundry and the ionic EXAMPLE II The conditions were the same as in Example I except that the electrodes were of refined steel and silver respectively. In this case the ammeter recorded ma. at the beginning of the washing process and recorded 45 ma. at that point in the process where all of the released dirt particles were encased in drops of washing liquid having opposite polarities.

As pointed out above the degree of dissociation or ionization of the washing liquid is independent of the kinds of dirt in laundry. However, different kinds of dirt are released from the laundry at different temperatures. Dirt in powder or particle form is released from the laundry when the temperature of the washing liquid is about 50 C. while oily or greasy substances are released from the laundry when the washing liquid temperature is about 90 C. The release of the dirt particles results in a dispersion in the washing liquid and the release of the oil or greasy particles in an emulsion of the liquid. In both cases, however, the process of the invention as described above functions in the same manner.

It will be understood that this invention is subject to modification in order to adapt it to different uses and conditions.

What is claimed is:

1. ln a process for controlling the washing cycle of a washing liquid of water and detergent wherein an aqueous washing liquid is formed from water and a measured amount of detergent, the improvement of the steps of continuously electrically measuring the ionization of the washing liquid and sensing the difference in the degrees of dissociation of the washing liquid at the beginning of the washing cycle and after the washing cycle has continued to a point where some dirt has been released from the laundry into the washing liquid,

and continuing the wash cycle in response to the difference in the degree of dissociation of the washing liquid at the beginning of the washing cycle and at a point in the washing cycle by one of introducing additional detergent or stopping the washing cycle if no change occurs in the degree of dissociation of the washing liquid over a period of time during the washing cycle.

2. In a process as claimed in claim 1 and the further steps of measuring the degree of dissociation of added water, comparing the degrees of dissociation of the added water and the washing liquid to determine the difference between said degrees.

3. in a process as claimed in claim 1 and the further or steps of generating a signal in response to a predetermined unsatisfactory degree of dissociation,

and introducing additional detergent in response to the generated signal 4. In a process as claimed in claim 1 and the additional steps of measuring the degree of dissociation per unit time of the detergent in the washing liquid,

and introducing additional detergent into the washing liquid in response to the degree of dissociation per unit time. 

2. In a process as claimed in claim 1 and the further steps of measuring the degree of dissociation of added water, comparing the degrees of dissociation of the added water and the washing liquid to determine the difference between said degrees.
 3. In a process as claimed in claim 1 and the further or steps of generating a signal in response to a predetermined unsatisfactory degree of dissociation, and introducing additional detergent in response to the generated signal
 4. In a process as claimed in claim 1 and the additional steps of measuring the degree of dissociation per unit time of the detergent in the washing liquid, and introducing additional detergent into the washing liquid in response to the degree of dissociation per unit time. 